1. Field of the Invention
The present invention relates to a method and algometer capable of controlling the rate of intensification of the pressure applied to a point, generally external of a patient's body.
2. Brief Description of the Prior Art
Pain is a subjective, complex phenomenon consisting of (a) a sensorial perception sometimes revealing a potential or real tissular lesion, and (b) the affective response provoked by this sensorial perception. As pain sensation is also psychic, objective evaluation thereof is difficult.
Presently, two main types of pain evaluation are currently used during clinical examination of patients: evaluation of the sensitivity of the affected tissues to pain, and evaluation of the "clinical pain". Evaluation of pain sensitivity is generally carried out by means of palpation of skin or underlying tissues (for example muscles), or by means of other more or less reliable methods. "Clinical pain" is usually evaluated from a verbal report of the patient; these verbal reports are generally unreliable since they depend on the patient's "pain memory" and since chronic pain may widely vary within a same day and from one day to the other.
Also, pressure algometers are available on the market to measure the pressure-pain threshold of a patient at a specific point or at several points of the patient's body. The pressure algometers presently available on the market are designed to apply mechanical pressure to the point(s) of interest of the patient's body and to measure the applied pressure. The patient is instructed to signal, as pressure is applied through the algometer, that the pain threshold has been reached either verbally or by pressing a pushbutton. The pressure measured at this moment is read and taken as the pressure-pain threshold. Using a pressure algometer, only one parameter is measured in contrast to manual palpation where the response and evaluation are more complex.
A prior art pressure algometer is presented in the article of Kai Jensen entitled "Quantification of Tenderness by Palpation and Use of Pressure Algometers" published in Advances in Pain Research and Therapy,. Vol. 17, page 170, edited by James R. Fricton and Essam Awad. Raven Press, Ltd., New York, 1990. This prior art algometer is provided with a display for pressure derivate to allow the user to intensify the pressure at a constant, adjustable rate. A first drawback of the prior art algometer is that the user has to correlate the reading of this display with application of pressure. Another drawback is that the display is installed on a read-out unit separate from the pressure-applying unit.